Motor Systems and Locomotion Flashcards
What is another word for motor neurone?
Motoneurone
What is the final effector pathway?
Brain to spinal cord to muscle
What does the lower motor neurone consist of?
Motoneurones which form a spindle like motorpool
Where are distil and proximal muscles represented in a motor pool?
Distil are lateral and proximal are medial
What is a motor unit?
Innervated muscle fibres connected to a motoneurone
What does the muscle spindle do for the CNS?
Constantly tells it it’s position in space
What is the muscle spindle?
The sensory apparatus of muscle- intrafusal fibres
What does the spindle detect?
Changed in muscle length
What do extrafusal muscle fibres do?
Form the bulk of muscle and generate tension. They receive motor innervation from alpha motor neurones.
Where do intrafusal muscle fibres receive their motor innervation from?
Gamma motor neurones
What is the Golgi tendon organ?
A mechanoreceptor which lies in a series of muscle fibres and detects changes in tension. It stops myself tearing and contributes to proprioception
What are the four groups of sensory afferents in a muscle spindle?
Primary afferent (1a)- senses stretch and rate of change in stretch Secondary afferent (2)- stretch 3: finer that 1a and 2- nociceptive from muscle From tendon organs (1b)- signal force change in muscle
What is a monosynaptic reflex?
Stretch reflex goes to muscle spindle 1a afferent goes to homonymous alpha motor neurone to output.
What is a polysynaptic reflex?
Crosses extension reflex (FRA reflex) goes to sensory afferent to interneurone to motor neurone to output.
How can the loss of a motor unit be overcome?
Make the rest of the motor units do more work
